Control system for elevators



July 1, 1930. w. F. EAMES CONTROL SYSTEM FOR ELEVATORS Filed Sept. 19, 1928 3 Sheets-Sheet 1 INVENTOR h/fl/fam FE'ames.

ATTORNEY July 1, 1930. w. F. E'AMEs CONTROL SYSTEM FOR ELEVATORS 3 Sheets-Sheet 2 F .ii? 4 11111 ll.1 1 d v v IIAH|\\\\ a ATTOI'QNEY July 1, 1930. w. F. EAMES CONTROL SYSTEM FOR ELEVATORS Filed Sept. 19, 1928 3 Sheets-Sheet 3 INVENTOR MY/famf. 50/7765.

ATTORNEY Patented July 1, 1930 UNITED STATES PATENT OFFICE WILLIAM F. EAMES, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC Q: MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA CONTROL SYSTEM FOR ELEVATORS Application filed September 19, 1928 Serial No. 306,803.

This invention relates to control systems and particularly to control systems for elevators, hoists, road vehicles and similar apparatus.

An object of the invention is to provide a light-responsive control unit for use in connection with apparatus of the above type.

Another object of the invention is to provide a single light-responsive control unit for use in connection with apparatus of the above type which is capable of selectively effecting a plurality of different control operations.

A further object of the invention is to provide a light-responsive control unit for use in connection with apparatus of the above type, whereby the cooperation between a single light source and a plurality of light-sensitive members is effective to initiate a plural- 2Q, ity of control operations.

The utility and details of construction of iny invention may best be appreciated after a general description thereof. For this purpose, I have shown my invention as embodied in an elevator control system which is described and claimed in the copending application of Harold W. Mattingly, Serial No. 291,- 992, filed July 11, 1928 and assigned to the Westinghouse Electric and Manufacturing Company, although it will be understood that it may have a general application.

Turning now to the drawings;

Figure 1 is a schematic diagram of circuits and apparatus embodying the invention.

Fig. 2 is a schematic diagram of circuits and apparatus applicableto the system shown in Fig. 1 whereby an elevator may be brought to rest at a predetermined position by control ling an electric circuit from that position.

Fig. 3 is a View. in perspective, of a lightsensitive control device embodied in the circuits and apparatus of Fig. 1..

Fig. 4 is a diagrammatic illustration of the relative positions of a plurality of light-sensitive control devices and intercepting means of Fig. 2 with respect to a floor through which a hatchway extends.

Fig. 5 is a top view, in' perspective, of a li ht-sensitive device embodied in the device 0 Fig. 3.

control device illustrated in Fig. 3.

Referring to Fig. 1, an elevator cage or car 1, suspended from a cable 2, extending over a hoisting drum 3 and counter-balanced by a weight 4, is caused to travel by a hoisting motor 5. The motor 5 comprises an armature 6 and a field winding 7 connected for energization to supply conductors 8 and 9. The speed of the motor 5 may be regulated by connecting its armature 6 to a variablevoltage generator 10, which may be driven at approximately constant speed by a motor 11, preferably shunt wound, that is connected for energization to the supply conductors 8 and 9.

The generator 10 comprises an armature 12, a series field winding 13, a separately excited field winding 14, and an auxiliary or demagnetizing field winding 15 for reducing the voltage of the generator to approximately zero value when the winding 14 is deenergized.

The field winding 14 may be selectively connected to the supply conductors 8 and 9 for energization by means of an up-direction switch 16 and a down-direction switch 17, each switch being provided with contact members a to f, inclusive. If the switch 16 is closed, the direction of the magnetic field produced by the winding 14 is such that the voltage impressed on the armature 6 is of that polarity which will cause the drum 3 to rotate in a counter-clockwise direction to elevate the car 1. If the switch 17 is closed,

the field is reversed, whereby the drum 3 is caused to rotate in a clockwise direction,

a thereby lowering the car 1.

WVhen the switches l6and 17 are both in their open positions, the contact members d thereof are closed, whereby the field winding 15 is connected across the terminals of the generator 10 and the motor 5.

The strength of the magnetic field produc'ed by the field winding 14, hence the voltage generated by the generator 10, may be varied by means of an accelerating resistor 18 connected in series in circuit relation with the separately excited field winding 14, and

short-circuiting or intermediate and highspeed switches 19 and 21 for short-circuiting or shunting sections 22 and 23, respectively, of the resistor 18.

The direction and speed of movement of the car 1 may be controlled by a car switch 24 on car 1 comprising a movable member or car-switch handle 25 provided with contact segments 26 and 27, and a plurality of stationary contact fingers 28 to 38, inclusive. The segments 26 and 27 are so proportioned that, when the segment 26 is in position to bridge any one of the contact fingers 30 to 33, inclusive, or 35 to 38, inclusive, the segment 27 is disengaged from the contact finger 28.

The actuating coils of the up and down-direction switches 16 and 17 are provided with an interlocking relay 39; the ac tuating coil of the intermediate-speed switch 19 is provided with interlocking relays 41 and and the actuating coil of the highspeed switch 21 is provided with interlocking relays 42 and 44. The relays 41 and 42 are operable to etiect deenergization of the switches 19 and 21 in sequence when the elevator is moving in an upward direction, provided the switch 16 is closed and the relays 43 and 44 are operative to control the sequential operation of the relays 19 and 21 when the car 1 is descending, that is, when the switch 17 is closed. The relays 39 to 44, inclusive, may be initially energized by means of a relay 45, which is controlled by the car switch 24;

Assuming that it is desired to start and accelerate the car 1 in an upward direction, the car-switch handle 25 is turned in a counter'clockwise direction, whereby the contact fingers 29 to 33 are bridged by the segment 26 in sequence.

Vhen the car-switch handle 25 is in position to bridge the contact fin ers 29 and 30, the contact finger 28 being su sequently disengaged from the contact segment 27 a circuit is established for energizing the coil of the relay 45 which extends from supply conductor 8, through a conductor 46, contact fingers 29 and 30, bridged by the segment 26, conductor 47, the coil of relay 45, and conductors 48 and 49, to the supply conductor 9. Therefore, the relay 45 is energized to close its contact members a, b and c.

hen the car-switch segment 26 bridges contact fingers 29, 30 and 31, a circuit is established for the coil of the up-direction switch 16, which circuit extends from the supply conductor 8, through conductor 46, contact members 29, 26 and 31 on the car switch 24, conductor 51, the coil of the updirection switch 16, and conductors 52, 53 and 49, to the supply conductor 9.

The up-direction switch 16, when closed, establishes a circuit for the relay 39 which extends from the supply conductor 8 through conductor 46, contact members a of relay 45, conductor 54, the coil of relay 39, and conductors 55 and 49, to the supply conductor 9. Another circuit is completed by the switch 16 for energizing the relay 41 which extends from supply conductor 8, through conductor 46, contact members I) of relay 45, conductor 56, the coil of relay 41, conductor 57, contact members f on the up-direction switch 16 and conductors 53 and 49, to the supply conductor 9. Similarly, a circuit for the relay 42 is completed which may be traced from supply conductor 8, through conductor 46, contact members 0 of relay 45, conductor 58, the coil of relay 42, conductor 57, contact members f of the up-direction switch 16, and conductors 58 and 49, to the supply conductor 9.

Upon the closing of relay 39, a holding circuit for the coil of the tip-direction switch 16 is completed which may be traced from the supply conductor 8, through conductor 46, conductor 59, the contact members of relay 39, conductor 60, contact members a of the lip-direction switch 16, the coil of up-dircction switch 16, and conductors 52, 53 and 49, to the supply conductor 9.

The up-direction switch 16 also completes a circuit for the field winding 14, that extends from supply conductor 8, through conductor 61, conductor 62, contact members I) of tip-direction switch 16, conductor 63, field winding 14, contact members 0 of up-direction switch 16, conductor 64 and the resistor 18, to the supply conductor 9.

It is to be noted that, if the up-direction switch 16 is energized, the field winding 15 is disconnected from the terminals of the generator 10 and the motor 5; also, if the switch 16 is deenergized or open, the circuit of the field winding 14 is open and that of the field winding 15 is closed. The energizing circuit of the winding 15 may be traced from a conductor 65, connected between the armature of the motor 5 and the armature of the generator 10, through the field winding 15, conductor 66, contact members d of the downdirection switch 17, contact members at of the l p-direction switch 16 and conductor 67, to conductor 68 that connects the other terminals of the armatures of the motor 5 and the generator 10.

The up-direction switch 16, having been closed, and the energizing circuit for the field winding 14 having been established, as hereinbefore traced, the car 1 will start in an upward direction at slow speed. In order to accelerate the car to intermediate speed, the intermediate-speed switch 19 must be closed to short-circuit the section 22 of the resistor 18. This is accomplished when the contact finger 32 of the car switch 24 is bridged by the se ment 26 to establish an energizing circuit or the coil of the intermediate-speed switch 19.

This circuit may be traced from the supply conductor 8, through conductor 46, contact members 29, 26 and 32, on car switch 24, conductor 71, the coil of the intermediate-speed switch 19 and conductor 70, to the supply conductor 9. Therefore, the intermediate-speed switch 19 closes its contact members I) to short-circuit the section 22 of the resistor 18. Therefore, the magnetic field developed by the field winding 14, and the voltage supplied to the motor 5 are increased to accelerate the car 1 to intermediate speed.

Upon the closing of the intermediate-speed switch 19, a holding circuit for the coil thereof is established which may be traced from the supply conductor 8 through conductors 46 and 59, through the contact members of the relay 41, which is closed, conductor 72, contact fingers a of the speed switch 19, the coil of switch 19 and conductor 70, to the supply conductor 9.

To accelerate the car 1 to full running speed, the handle 25 of the car switch 24 is actuated to the position wherein the contact.

fingers 29 and 33 are bridged by the segment 26. A circuit for the high-speed switch 21 is thereby established and may be traced from the supply conductor 8, through the car switch 24, conductor 73, the coil of high-speed switch 21 and conductor 70, to the supply conductor 9. Therefore, the switch 21 is closed and the section 23 of the resistor 18 is short-circuited by the contact members I) of the switch 21, whereby full voltage of the conductors 8 and 9 is impressed on the field winding 14. The voltage. of the generator is, therefore, increased to its maximum value to increase the speed of the motor 5, and the car 1 to its full running speed.

Upon the energization of the switch 21, a holding circuit for the coil thereof is completed which extends from the supply conductor 8, through conductor 46, the contact members of relay 42 (which is closed), conductor 74, contact members a of high-speed switch 21, the coil of switch 21 and conductor 70, to the supply conductor 9.

If the handle 2501? the car switch is held in the position wherein the contact fingers 29 and 33 are bridged by the segment 26, the car 1 will continue to travel in an upward direction at its full running speed. When it is desired to stop the car at a floor it should be brought to rest exactly at the floor level and, to accomplish this result, I have provided means forinitiating deceleration at the proper distances from the floor which will permit the car to land exactly level therewith. This means includes light-sensitive control devices and 76 carried by the car and arranged to deenergize speed relays 21 and 19 and direction switch 16 in sequence as the car aproaches the floor level. The devices 75 and 6 are energized upon the return of the handle 25 to the position shown in Fig. lot the trio cell 77 possesses the characteristic that,

when beams of light produced by the light 78 are projected thereon, current will flow from the supply conductor 8, through conductor 46, the light-sensitive device 77 and the coil of the relay 39, to the supply conductor. 9.

The light-sensitive device 76 comprises a light-producing member or incandescent light and light-sensitive devices or photoelectric cells 80 and 81. The 1i ht-sensitive device 80 controls the circuit 0 the coil of the relay 41, which, in turn, controls the holding circuit for the. actuating coil of the intermediate-speed switch 19, when the car is moving in the upward direction, and the light-sensitive device 81 controls the holding circuit for the actuating coil of the highspeed switch 21.

When the car-switch handle 25 is returned to the position shown in Fig. 1, a circuit is established for the lights 78 and 79. The circuit established for the lights 78 and 7 9, upon the centering of the car-switch handle 25, may be traced from the supply conductor 8 through conductor 46, contact members 29, 26, 27 and 28 of the car switch 24, the lights 78 and 79, conductor 82, contact members e of the up-direction switch 16 and conductor 49 to the supply conductor 9.

Subsequent to energizing lights 78 and 7 9, relay 45 1s deenergized, since contact member 30 on car switch 24 is opened after contact members 27 and 28 are engaged. Therefore, when the relay 45 is deenergized, the circuits for the relays 39, 41 and 42 are transferred to, and are maintained through, the photoelectric cells 77, 80 and 81.

The circuit maintained for the relay 39, by the selenium cell 77, extends from the supply conductor 8, through the conductor 46, the photo-electric cell 77, the relay 39 andconductors 55 and 49, to the supply conductor 9. The circuit maintained for the relay 41 by the selenium cell 80 may be traced from the supply conductor 8, through the conductor 46, the photo-electric cell 80, the relay 41, conductor 57, contact members 7 of the updirection switch 16 and conductor 49, to the supply conductor 9. Similarly, the circuit maintained for the relay 42 by the cell 81- may be traced from the supply conductor 8 through the supply conductor 46, the photoelectric cell 81, the relay 42, conductor 57, contact members f of the Lip-direction switch 16 and the conductor 49, to the supply conductor 9.

Assuming that the car has been accelerated to its full running speed and that it is desired to bring the car 1 to rest level with a fioor indicated by a broken line 83, this result may be obtained by stationarily mounting a plurality of shields 84, S5 and 86, of any suitable opaque material, in the hat-chway adjacent to the floor 83 past which the car moves. The shields 84 and 85 are spaced vertically from each other at predetermined distances from the floor 83 and are spaced horizontally from each other so that the shield 85 will pass between the light 79 and the photo-electric cell 30, and the shield 84 will pass between the light 79 and the photo-electric cell 81. The shield 86 is positioned approximately at the level of the fioor 83 and in a position to intercept beams of light from the light 78 projected on the cell 77. It is to be understood that, in practice, the positions of the light-sensitive control devices and those of the shields in the hatchway, will be so adjusted that the car 1 is properly dccelerated grid brought to a stop level with a selected oor.

As the car-approaches the fioor, the shield 84 will intercept beams of light projected from the light 7 9 on the photo-electric cell or light-sensitive device 81. Upon the darkening of this cell, the current-carrying characteristic thereof changes to effect a reduction in the current fiowing through the coil of the relay 42 to such value that the relay is dropped out to open the holding-coil circuit of the high-speed switch 21, hereinbefore traced. The coil of the switch 21, being deenergized, the high-speed switch is opened to re-insert section 23 of the resistor into the circuit of the field winding 14 to reduce the voltage of the generator 10 and the speed of the motor 5.

As the car continues to approach the floor, the shield 85 passes between the light-sensitive device 80 and the light 7 9, thereby darkening the same and effecting a change in its current-carrying characteristic. This change in characteristic of the light-sensitive device operates to reduce the flow of current through the coil of the relay 41 to such value that the relay drops out and opens or deenergizcs the holding circuit for the actuating coil of the intermediate-speed switch 19.

The holding coil of the switch 19, having been deenergized, the switch is opened and the section 22 of the resistor 18 re-inserted in the circuit of the field winding 14 to further reduce the voltage of the generator 10 and the speed of the motor 5. The car is now moving at slow or landing speed. When the car reaches approximately the level of the floor 83, the shield 86 passes between the light 78 and the photo-electric cell 77 to darken the same. A change in its characteristic is thereby effected, and the current flowing in the coil of the switch 39 is reduced thereby to such value that the relay 39 drops out, whereby the holding circuit for the coil of the up-direction switch 16 is deenergized.

The holding circuit for the coil of the switch 16 having been interrupted, the switch 16 drops out to deenergize the field winding 14 and to connect the field winding 15 for energization across the terminals of the motor 5 of the generator 10. When the field winding 15 is energized, the flow of current is in such direction that a magnetic field is developed in opposition to the field produced by the residual magnetism of the windings 13 and 14. The voltage of the generator 10 is, therefore, reduced to Zero, or approximately Zero, to effect substantially an instantaneous stop from slow speed when the car has reached the level of the floor 83.

When the up-direction switch 16 is opened, the circuit for the lights 78 and 79 is broken. Therefore, in order to again start the car upward, the car-switch handle must be actuated through the positions previously mentioned herein, to effect a sequential reclosing of the up-direction switch 16 and the accelerating or speed switches 19 and 21.

In order to start the car in a downward direction and accelerate it to its full running speed, the car switch handle 25 is moved in a clockwise direction, whereby the contactbridging members 35, 36, 37 and 38 are bridged in sequence by the contact segment 26. When the contact finger is bridged, the relay is closed, the circuit of which has hereinbefore been traced, and, when the contact finger 36 is bridged, the down-direction switch 17 is closed to connect the field winding 14 in series with the resistor 18 across the supply conductors 8 and 9.

Upon the closing of the switch 17 the circuits of the coils of the relays 39, 43 and 44 are established through the switch 17 in the same manner as the circuits for the coils of the relays 39, 41 and 42 are established through the switch 16. The relay 39 operates to establish a holding circuit for the coil of the down-direction switch 17, and the relays 43 and 44 function to control the holdingcoil circuits or the short-circuiting or speed switches 19 and 21, when they have been energized by the car switch 24.

When the contact finger 37 is engaged by the segment 26, the coil of the switch 19 is energized, and the section 22 of the resistor 18 is short-circuited to thereby effect an increase in the voltage of the generator 10 and the speed of the motor 5. When the contact finger 38 is engaged by the segment 26 of the car switch, the circuit of the switch 21 is established to close the high-speed switch 21 and thereby short-circuit the section 23 of the resistor 18 to further increase the voltage of the generator 10 and the sgeed of the motor 5. The car is now moving ownwardly at full running s eed.

. In order to dece erate the car from full running speed and to bring it to a stop, level with the floor 83, a light-sensitive control device 88, mounted on the car 1, and shields 89 and 90 stationarily mounted in the hatchway are provided. The shields 89 and90 are spaced both verticallyv from each other at predetermined points above the floor 83, and laterally, as shown in Fig. 1.

The light-sensitive device 88 comprises a light-producing member or an electric light 91 positioned between light-sensitive devices or photo-electric cells 92 and 93. The photoelectric cell 92 controls the circuit of the actuating coil for the relay 43, and the cell 93 controls the circuit of the actuating coil for the relay 44 when the car-switch handle 25 is in its central or normal position (see Fig. 1), in the same manner as was described for relays 41 and 42 and photo-electric cells 77 and-80 when the car moved upwardly.

When the car-switch handle 25 has been centered, as shown in Fig. 1, (the car being driven downwardly at its full running speed) the lights 78 and 91 are connected in seriescircuit relation across the supply conductors 8 and 9. The circuit for the lights may be traced from the supply conductor 8, through the contact members 34, 26, 27 and 28 of the car switch 24, lights 78 and 91, conductor 94, contact members e of down-direction switch 17 and conductors 53 and 49, to the'supply conductor 9. i

As the car approaches the floor 83, the shield 89, constructed by any suitable opaque material, passes between the light 91 and the photo-electric cell 93, thereby darkening the same. The resistance of the cell 93 is, therefore, increased to such value that the current through the actuating coil of the relay 44 is reduced to a value at which it drops out to open the holding-coil circuit of the highspeed switch 21. The high-speed switch 21 having been opened, the section 23 of the resistor 18 is re-inserted in the circuit of the field windin 14 to effect a reduction in the voltage of t e generator 10, and avslowing down of the motor 5 to intermediate speed.

Deceleration of the car from intermediate speed to slow speed is effected when the shield 90 passes between the light 91 andthe photoelectric cell 92 to darken the same. The darkening of the cell causes its resistance to be increased to such value that the current in the actuating coil of the relay 43 is decreased to a value at which it opens or dro s out. The relay 43, when open or droppe out, interru ts the holding circuit for the actuating COll of the low-speed switch 19. The lowspeed switch. 19 having been opened, the entire resistor 18 is connected in circuit with the field winding 14 to further reduce the voltage of the generator 10 and the speed of the motor 5 to s ow speed.

When the car has reached, approximately, the level of the floor 83, the shield 86 passes between the light 78 and the photo-electric cell 77 to cause the relay 39 to drop out, whereby the holding circuit for the actuating coil of the down-direction switch 17 is deenergized, whereby the switch 17 is opened. Upon the opening of the switch 17 the field winding 14 is deenergized, and the field winding 15 energized, in the manner hereinbefore stated, to reduce the voltage of the generator 10 to zero, and to stop the motor 5 when the car 1 is level with the floor 83.

, From the foregoing description of the operation of the circuits and apparatus embodying myeinvention, it is obvious that the car 1 may operated at full running speed or any predetermined intermediate speed, depending upon the position of the car-switch handle 25, past any number of floors by holding the car switch in a position corresponding to the particular running speed desired. To stop the car at a floor being approached, the car-switch handle 25 is centered, as shown in Fig. 1, whereby the lights 78 and 79 are lighted (if the car is moving in an upward direction) and the relay 45 deenergized to render the light-sensitive control devices operative to deenergize the intermediate and high-speed switches 19 and 21 and the relay 39 in sequence as the shields 84, 85 and 86 are passed to bring'the car to stop level with the floor 83. The same result may be accom-- plished if the car is moving downwardly through the hatchway.

In the elevator-control system described above and illustrated in Fig. 1, the movement of the car 1 is controlled by the agencypf the car switch 24, the light-sensitive control devices 75, 76 and 88, and the shields 84, 85, 86,

Y89 and 90. However, in some installations of my elevator system, it may be desirable or even necessary to provide means whereby the car 1 may be stopped automatically at the several floors by passengers who are awaiting to board the elevator at the respective floors when it is moving in the direction in which they may wish to be carried. 7

In the event that it is desired to so utilize my control system, the system described above may be provided with automatic stopping means that comprises, in general, a control system of the type wherein the car may be automatically stopped by passenger-controlled push-button switches located at the several floors. I have illustrated such a systerm in Fig. 2. A passenger at any floor, who desires to board an elevator as it is ascendor, it he desires to descend, he may close a down push-button switch.

The automatic means illustrated in Fig. 2 as applicable to my elevator system for stepping the car automatically at any one of several floors, comprises passenger-controlled push-button switches 95 and 96, a floor selector 97, a stopping relay 98 controlled by the floor selector and relays 99 and 100 for energizing the fioorselector. Theswiteh95is actuated to energize the relay99 whenthe person desires to travel upwardly, and the switch 96 is actuated to energize the relay 100 if the person desires to travel downwardly. \Vhile I have illustrated only one set of buttons 95 and 96, it is to be understood that one set will be provided for each floor past which the car moves.

In the event that it is desirable to provide for automatically stopping the car by the car operator at any floor corresponding to the floor called by a passenger in the car, pushbntton switches 101 and 102 may be mounted in the car for actuating the floor-selector energizing relays 99 and 100. \Vhile only a set of floor push-button switches 101 and 102 for one floor have been illustrated as carried by the car, it is to be understood that the car may be provided with as many sets of push-but ton switches as there are floors past which the car may move.

A floor selector of a type similar to that usually employed with elevator signals, or of the type disclosed in the copending application of Frank E. Lewis, Serial No. 353,452, filed July 25, 1929, may be utilized for transferring calls registered on push-buttons 95, 96, 101 and 102 to cause the operation of stopping relay 98. This floor selector may com prise continuous contact strips 103 and 104 connected in circuit with stopping relay 98. Arranged adjacent continuous contact strip 103, I have illustrated a plurality of contact segments, one of which is designated by the reference character 105 connected to the pushbutton switch 102 and the contact members of call-registering relay 100. It is to be understood that a similar segment will be connected to each of the call-registering relays and each of the car buttons associated with other floors past which the car moves. In like manner, the contact segment 106 is connected to the contact members of call-registering relay 99 and push button 101.

The floor selector also includes a pair of normally closed switches 108 and 109 in cireuit with the coils of relays 100 and 99, respectively.

A movable arm 107, driven in correspondence with the movements of the car, traverses the contact strips and segments in a well known manner and through bridging member 110 bridges contact strips 104 and segment 106, when the car is travelling upwardly, and through bridging member 111, bridges contact strips 103 and segment 105 when the car is travelling downwardly.

It will be observed that, when the car is level with floor 83, (indicated by dotted lines) wedging members 112 or 113, dependent upon the direction of which the car is travelling, will enter between and open contact members 108 and 109, respectively.

The contact members a of the stopping relay 98 will be connected in series relation with conductor 47 between contact fingers 35 and 30 of car switch 24 and relay 45, while the contact members Z of the said stopping relay 98 will be connected between the contact linger 28 of the car switch 24 and the lights 78, 79 and 91. It is evident, therefore, that, when the stopping relay 98 is energized, the relay 45 is deenergized, and the lighting circuit for the lights 78 and 79 established, it the "car is moving in an upward direction, and the lights 78 and 91 are energized it' the car is moving in a downward direction. The light-sensitive or photo-electric cells 77, 80 and 81 are, therefore, energized when the car is moving in an upward direction and the car is subjected to the control of the system hereinbefore described.

Similarly, if the car is moving in a downward direction, the light-sensitive or photoelectric cells 77, 92 and 93 are energized when the car is moving in a downward direction to bring the car to a stop level with the floor, in the manner set forth above.

Assuming that the car is ascending and approaching the floor 83 at which a passenger wishes the car to stop, and that the carswitch handle 25 has been moved to a position hereinbefore described to effect fullspeed operation of the elevator, then, in order to stop the car, the push-button switch 95 is closed to establish a circuit from the conductor 8, through the coil of the relay 99, conductor 115 and the normally closed switch 108 on the floor selector 97, to the supply conductor 9. The relay 99 is, therefore,'closed, and a holding circuit is established for the coil thereof Which extends from the conductor 8, through the contact members of the relay 99 and the coil thereof, to the conductor 9.

As the car 1 approaches the floor, contact strip 104 and segment 106 will be bridged by the contact-bridging member 110 carried on the movable arm 107. A circuit for actuating the stopping relay 98 is thereby established, which extends from supply conductor 8, through the contact members of relay 99, conductors 116 and 117, contact segment 106, contact member 110 and strip 104, conductor 118 and the coil of the relay 98, to the supply conductor 9.

l/Vhen the relay 98 is energized, the circuit for relay 45 is broken, and the relay deenergized. The contact members a, 7) and 0 ot the relay 45 are, therefore, disengaged, whereby the light-sensitive control devices are rendered operative to control the relays 39, 41 and 42 as previously described herein.

Upon the energization of the stopping relay 98, a circuit is established through the contact members 6 thereof for the lights 78 and 79, which may be traced from the conductor 8, through conductor 46, the car switch 24, contact finger 28 thereof, conductor 119, contact members I) of relay 98, and the lights 78 and 79., to the supply conductor 9, a circuit previously described for these lights.

The lights 7 8 and 79, being energized, the selenium cells 77, 80 and 81 are energized, and, as the car 1 continues to approach the floor, the shields 84, 85 and 86 will pass between the lights and the photo-electric cells in the manner hereinbefore set forth, whereby the relays 39, 41 and 42 will be dropped out in sequence to decelerate the car and bring it to a stop, level with the floor 83.

When the car arrives level with the floor 83, the normally closed switch 108 on the floor selector is opened by the wedging member 112 carried by the movable arm 107. Therefore, the energizing circuit of the relay 99 is broken, and, when this relay is deenergized, it opens'the circuit to the stopping relay 98 and interrupts also the circuit of the lights 78 and 79.

Similarl if a passenger desires to travel downward y with the car, he may operate the push-button switch 96, whereby'a circuit is established through the coil of the relay 100 which may be traced from supply conductor 8, through the switch 96, the coil of the relay 100, normally closed switch 109 and a conductor 121, to the supply conductor 9. When the relay 100 is closed, a holding circuit for the coil thereof is established which extends from the supply conductor 8, through the contact members and the coil of said relay, to the supply conductor 9.

As the car approaches the corresponding floor, when moving in a downward direction, the contact member 111, carried by the arm of the floor selector 97, bridges the continuous contact strip 103 and the contact segment 105. A circuit for the relay 98 is thereby established which extends from the supply conductor 8, through the contact members of the relay 100, the continuous contact strip 103, segment 105, and contact member 111, conductor 118 and the coil of the relay 98, to the su 1y conductor 9.

hen the relay 98 is energized, it breaks the circuit to the coil of the relay 45 and establishes a circuit for the lights 77 and 91. As the car continues to approach the floor,

the shields 89, and 86 operate to decelerate and stop the car in the manner hereinbefore set forth. Also, when the. car arrives level with the floor, the wedging member 113 of insulating material, carried by the arm 107 of the floor selector 97, opens, the normally closed switch 109 to deenergize the relay 100,

whereby the relay 98 is caused to operate to deenergize the lights 78 and 91.

' The car may also be brought to a stop by the operator of the car by actuating the one or the other of the push-button switches 101 and 102. The switch 101 is utilized to stop the car when it is approaching the floor from below, and the switch 102 when the car is approaching a floor from above. The pushbutton switches 101 and 102 control the respective push-button relays 99 and 100 in the same manner as do floor push-button switches and 96.

Turning now to the elements of the system described, which I claim as my invention, a preferred form of the light-sensitive control devices 75, 76 and 88, when selenium cells are employed, is illustrated in Fig. 3 of the drawings. Since these control devices are similar in construction, it is believed necessary to describe only one of them and for purposes of explanation, the complete device in Fig. 3 will be given the numeral 76,-indicating generally a light-sensitive control device. The device 76 comprises a casing 122, having a back wall 123 and side walls 124 and 125. The front of the casing is provided with walls 126, 127, 128 and 129 extending into the easing and parallel with the walls 124 and 125. The inner ends of the walls 126 and 127 and 128 and 129 may be connected by walls 130 and 131, respectively, and the walls 126 and 129 may be secured to the side walls 124 and 125 in any suitable manner. The outer ends of the walls 127 and 128 may be joined by connecting wall 132.

As shown in Fig. 3, the walls 124 and 126 are spaced from each other to receive the light-sensitive device or selenium cell 81, and the walls 129 and 125 are spaced to receive the selenium cell or light-sensitive device '80.

The light 79 is mounted in the casing a d j acent the back wall 123. In order that a beam of light may be projected between the walls 127 and 128, a reflector 133 is disposed behind the light 79. The beam of light so projected into the space between these walls may be reflected on the 1ight-sensitive or selenium cells 80 and 81, by means of mirrors 134 and 135. The beam of light striking on the mirror 134 is reflected through an opening 136 in the wall 127 to fall on the selenium cell 81. Similarly, the beam of light from the light 79 striking on the mirror 135 is reflected on the selenium cell 80, through an opening 137 in the wall 128.

As. shown in Fig. 3, the shield. 84, which may be mounted on the walls of the hatchway, is positioned to pass between the walls 126 and 127, thereby intercepting the beam of light projected on the selenium cell 81. The shield 85, not shown in Fig. 3, may be mounted in the hatchway and so positioned that it will pass between the walls 128 and 129 to intercept beams of light projected on the selenium cell 80.

The terminals of the respective selenium cells 80 and 81 may be secured to the back wall 123 of the casing by means of conductors shown by broken lines 138, 139 and 149. The lower terminal of the selenium cell 81 is not shown, but may be secured to the back wall in any suitable manner.

The selenium cells 80 and 81 are shown diagrammatically in Figs. 5 and 6 as comprising an assembly of a plurality of plates, three of which, 141, 142 and 143, are shown, having strips of insulating material and 145 interposed between adjacent plates and secured together in any suitable manner. The front edges of all of the plates may be connected together by a coating of lightsensitive metal, for example, selenium, as indicated by the dotted surface 146. Every other plate in the assembly is connected in any suitable manner to a common terminal while the remaining plate is connected to another terminal.

l/Vhen a beam of light is directed against the surface 146, an appreciable current will pass between the plates 141, 142 and 143, because the resistance of the selenium is low, but, if this surface is darkened, as by intercepting a beam of light projected thereon, the resistance of the metal coating becomes high and reduces the value of current flowing between them.

The relative position of the light-sensitive "ontrol devices 75, 76 and 88, when mounted on the ear, is shown in Fig. 4. The position of the shields 84, 85, 86, 89 and 90, which are mounted in the hatchway on the walls thereof, is shown also in Fig. 4. The shield 86 is secured in the hatchway substantially level with the floor 83, and the shields 84 and 85 are positioned below the floor and the shields 89 and 90 are positioned above the floor. If the car is moving in a downward direction, the shield 89 passes between the light and the selenium cell 93 and the shield 90 between the light and the cell 92. When the car is level with the floor, the shield 86 passes between the light 78 and the selenium cell 77.

If the car is below the floor and is approaching it from below, the shield 84 passes between the walls 126 and 127 to intercept the beam of light reflected on the selenium cell 81 from the light 79, and, subsequently, the shield 85 passes between the walls 128 and 129 to intercept the beam of light reflected on the selenium cell 80.

It has been found that, in some applications of the light-sensitive-cont-rol device 76 to the elevator control system described herein, the operation of the car 1 cannot'readily be controlled within the exact limits required. This is particularly true with reference to the final stopping of the elevator level with any of the several floors past which the car moves. In passenger elevators, it is usually required that the car come to a stop within from one-fourth to one-half inch above or below the floor. When utilizing the light-sensitive-control device 76, in which selenium cells are utilized as the light-sensitive element, it has been found that it is difficult to stop the car at the floor within such close limits. However, the selenium cells operate satisfactorily to modify the speed of the car between the floors.

Therefore, in order to provide a light-sensitive-control device which will stop the car level with the floor within the close limits necessary in passenger elevator systems, it is proposed to use the light-sensitive-control device 147 illustrated in Fig. 7. The lightsensitive device 147 is similar, in many respects, to the control device 76 and comprises, in general, a casing 148 having compartments 149, 150 and 151 separatedfrom each other by partitions 152 and 153.

A light-producing member or incandescent lamp 154 is mounted in the compartment 150 which light-producing member is provided with a reflector 155 for projecting beams of light on the mirrors 134 and 135.

In the respective compartments 149 and 151 are mounted'photo-electric tubes 156 and 157. The photo-electric tubes 156 and 157, when exposed to a beam of light, are capable of passing a current of a predetermined value when a definite voltage is applied thereto, but if the beam of light is intercepted, the cells will not pass a current at this voltage.

The beams of light projected from the light-producing member 154 are reflected from the mirror 134 through a relatively narrow slot or aperture 158 provided in a wall 159 of the compartment 151, the width of the slot bein such as will cause the car to stop within t e limits required. The beam of light passing through this aperture strikes a mirror 160 which reflects the beam on the photo-electric tube 157, thereby rendering it operative to permit current to flow therethrough.

The beams of light, striking the mirror 135, are reflected through a relatively narrow slotor aperture 161 provided in a wall 162 of the compartment 149, the width of the slot being such as will cause the car to stop within the close limits required. This beam of light strikes a'mirror 163 and is reflected on the photo-electric tube 156, thereby rendering it operative to pass an electric current therethrough.

The light-sensitive-control device 147 may be mounted on the elevator car 1 in substantially the same manner and sition as the light-sensitive-control device 6. When so mounted, the shield 8 (see Fig. 3) will pass through a recess 164 provided in the front-of the casing 144 to intercept the beams of light passing through the sIot or aperture 158, thereby efiectin a darkenin of the photo-electric tube 15 and to ren or it incapable of passing any electric current at the voltage which is normally impressed thereon. Likewise, when the car is at another predetermined position, the shield 85 will pass through another recess 165 provided in the front of the casing 147 to intercept beams of light passing through the slot of aperture 161 to thereby darken the photo-electric tube 156, whereby it is rendered incapable of passing an electric current at the voltage normally impressed thereon.

The photo-electric tubes 156 and 157, which it is proposed to utilize in the control systern described herein, are illustrated and described in a co-pending atent application of Dewey D. Knowles, serial No. 144,819 and filed October 28, 1926.

The photo-electric tube there described is provided with a photo-sensitive cathode 166 and an anode 167 which are electrically connected to res ective terminals 168'and 169.- If a beam of ight is rojected on this photoelectric tube and a v0 ta e of a predetermined value is impressed on tie terminals 168 and 169, a current will flow from the photo-sensitive cathode to the anode which will be of a value sufficient to operate relays ap licable to the control system herein described.

By my invention, I have provided a control system for electric elevators, whereby elevators may be accelerated from rest to full running speed, or to a plurality of intermediate speeds, by the actuation of a car switch from a normal position to its operating or accelerating positions. The control system includes leveling means whereby the car may be decelerated automatically and brought to rest level with any one of several floors past which the car moves by returning the car switch to its normal position after it has been actuated to. any of its running positions.

The leveling means comprises a plurality of light-sensitive devices or selenium cells and llght-producing members mounted on the car, for energizing the cells, and a plurality of shields, of suitable opaque material, stationarily mounted in the hatchway adjacent to the several floors and in spaced relation to each other, for deenergizing the selenium cells in a predetermined sequence, whereby the control s stem is caused to function in such manner that the car is decelerated in ste s and brou ht to rest level with any one of t e several oors.

The light-sensitive control devices are free from moving parts, are simple in construction and light in weight so that the elevator cars equipped with such apparatus will be materially lighter than cars equipped with apparatus, for accomplishing the same or a simi ar purpose, consisting, generally, of solenoidally or ma etically actuated contactors.

While I have set forth a preferred embodiment of my invention, it is to be understood that various modifications may be made therein without departing from the spirit and scope of my invention. It is desired, therefore, that only such limitations shall be placed upon the invention as are imposed by the prior art and the appended claims.

I claim as my invention:

1. A light-sensitive control device for a car movable in a hatchway between predetermined points comprising a casing mounted on the car, a light-producin member in the easing, a plurality ofi lig t-sensitive devices mounted in the casing 1n different planes, a reflector in the casing positioned to project a beam of light on each light-sensitive device when the light producing member is energized, and a plurality of shields supported by the hatchway, each of the respective shields being positioned at predetermined points in the hatchway and spaced both horizontally and vertically relative to each other in such manner that, as the car moves in the hatchway past the shields, the beams of light are intercepted in a predetermined sequence.

2. A light-sensitive'control device comprisinga plurality of spaced shields, a casing, a 1g t producing member, a plurality of lightsensitive devices supported 1n said casing, and means for projecting beams of light from the light-producing member on said li ht-sensitive devices, sald casing being provided with recesses between the respective light-sensitive devices and said projecting means through which said shields may be moved to intercept said beams of light.

' 3. A light-sensitive control device comprising a plurality of shields, a casin having a back wall and two side walls, a lig t-produ'cing member supported in the casing adjacent the back, means for projecting a beam of light towards the front of the casing and between the side walls, a light-sensitive device supported by each side wall at the front thereof, and a mirror supported by the casing at the front thereof for projecting said beam of light on each of said light-sensitive devices, ortions of said casing being open at the top, ttom and front between the mirror and the light-sensitive devices,.thereby defin ing a passageway through which said shield may move to intercept t e beams of light reflected on the light-sensitive devices.

In testimony whereof, I have hereunto subscribed my name this 5th day of September,

WILLIAM F. EAMES. 

